An integrated 6×4mm2 LTCC front end module for WLAN radio applications

This paper presents a highly integrated front end module (FEM) for 802.11abgn WLAN applications in a compact 6×4×1.1mm³ module based on LTCC substrate technology with embedded passives. For the transmit path the FEM integrates a dual band (2/5GHz) GaAs HBT MMIC linear power amplifier, transmit diplexer and a pHEMT SPDT RF switch leading to a single antenna output. For the receive path the FEM includes a receive diplexer and 2/5GHz baluns. All this integration results in the smallest package size with the highest performance reported in the open literature for 802.11abgn FEM of this architecture. In the 2.5GHz transmit path the fully matched power amplifier provides at the antenna port 32dB small signal gain and 18-19dBm linear power with 802.11g 54Mbps OFDM at 3% EVM and 160mA current consumption. For the 5GHz transmit path the fully matched power amplifier provides at the antenna port 32dB small signal gain over the 5.15-5.85GHz band with ±0.4dB gain flatness and 16.5-17dBm linear power with 802.11a 54 Mbps OFDM at 3% EVM and 150mA current consumption. For both the 2 and 5GHz receive paths the differential amplitude imbalance is less than ±1dB and the differential phase is 180 ±10 degrees.